Heat and worms in Perth – how to keep your worms cool and happy

This Summer in Perth is going to be a scorcher. We don’t want to cook our worms. Worms are part of the family and are expensive to replace. Worms work tirelessly to turn our waste into super great fertilisers.

So show your worms a little love when they need it most.

Your compost worms are happiest between 15 and 26 degrees Celsius. Worms become a little sluggish when it gets much hotter than 26 but they will be ok up until about 33 or 34 degrees.

When the mercury reaches for 34 and above it is important to implement some measures to keep your little friends comfortable.

15-26 Ideal

27-34 Slow and sluggish

35+ Struggling – send help

So what can you do? We have compiled a list of all the different ways we have found can help get your worms through a super hot day. Play around with these options and find what works for you and your worm friends.

1. Shade – crucial

Getting the location right is the first step in keeping your worms cooler through summer. Direct sun can cause a worm farm to heat up very quickly so choose a position with full shade all day. The South side of your house would generally get more shade. The deeper shade the better, and pay some attention to the ventilation through the area. The breezier the better.

If you don’t have a suitable spot outside in full shade you could bring your worm farm inside or into a garage or porch. A moveable worm farm with wheels makes this job easier.

A worm farm can be kept in a well-ventilated garage, under a carport, on a porch, beneath a shady tree, or in a shed, laundry or basement. A happy worm bin won’t smell or attract pests.

If none of these are an option you may need to consider erecting a small shade structure. Get creative! My worms are down a narrow passageway at the side of the house and they get an hour of morning sun. On very hot days I wedge an old boogie board between the house and the fence on an angle to block that hour of sun.

2. Check on your worms

Sounds silly but if you’ve had worms for a little while you may be getting better at ‘reading’ them.

Check on your worms regularly and see what they are doing. Usually the bedding is cooler than the air as soil takes longer to heat up. So if conditions in the bin are good the worms should dive down into the middle to find a cooler area, particularly if you have a deep flow-through bin like a Hungry Bin. If you can’t see any worms in the top this is likely where they are. If you pull back the top few inches you may be able to see them and assure yourself that they are ok.

However if you find your worms up the sides and inside the lid en masse (not just a few), they are either trying to escape something in the bin they don’t like (any uneaten smelly food for example), or they are too dry (see 3 below) or too hot.

Stressed worms mass in a ball, often around the edges or in a corner of the bin. If you see these types of behaviours you will need to consider what is going on and implement appropriate measures.

3. Moisture – get it right

Worm bedding should be damp but not wet. Worms will suffer if the bin is too dry.

A good way to tell if it is too dry is to take a handful of the compost in the bin and give it a good squeeze (remove worms first of course). You should be able to squeeze a few drops out. Any more and it is too wet. No drops at all and it is too dry.

A hot day in Perth can definitely dry out your worm farm a little so it may be a good idea to add a little cool water on a hot day. If you use the hose make sure it hasn’t been sitting in the hot sun.

Be careful not to add too much. You shouldn’t need to hose them down continuously. Adding too much water can turn your worm farm in to a hot soupy mess and create anaerobic (smelly) conditions.

A worm farm with good free drainage is essential to ensure excess moisture drains from the bin and doesn’t drown your worms. If your worm farm has a tap be sure to open it so that excess moisture can drain out.

4. The Coolgardie safe – try it

Invented in the 1890’s the Coolgardie safe was an effective, low-tech way of keeping food cool. It used wet hessian to lower the temperature inside a wooden framed food safe through evaporation of the water in the hessian.

You can recreate gold rush history using the same evaporative cooling principles to keep your worms happy.

Drape a wet hessian bag (or an old towel or sheet) over the top of your (closed or open) worm farm. Either keep wetting the bag as it dries or sit a large bottle of water on the top. If you poke small holes in the bottom of the bottle it will slowly drip and keep the bag wet. Alternatively rest one end of the bag in a bucket of water and it will continue to ‘wick’ the water up as it evaporates.

If you are lucky enough to be a recipient of the Fremantle Doctor you will find this method to be super effective. If not, you can always point a fan at it, or implement additional measures from the list below.

5. Ice Ice baby

This is my go-to hot day quick fix.

Keep a couple of old plastic bottles (2L is good) full of water in the freezer. When the temperature heads towards 34, pop a frozen water bottle in the middle of the worm farm and push it down a couple of inches. Move any worms out of the way as they won’t be able to move if you put the ice right on them.

This will keep the core temperature down, creating a cooler zone where the worms can hang out. Rotate the two bottles if you have a few hot days in a row.

You shouldn’t need to open the lid of the bottle if the bin is moist enough (see point 3 above) as you don’t want to make the bin too wet.

6. Insulation

Adding a layer of insulation inside the worm farm can help keep the bin at a more even moisture level. It can also help keep the bin darker and cooler.

You can purchase a special worm blanket if you like, but a wet hessian sack or layer of wet cardboard or newspaper are all perfect for this purpose.

Food goes underneath the layer of insulation.

7. Slow down or stop feeding

Worms tend to slow down eating and reproducing during heat waves, so slow down feeding them fruit and vegetable scraps as they will just sit and rot. Rotting food heats up and can cook your worms from the inside out. Uneaten food also smells in the heat and your worms may try to escape.

Remove anything that is starting to smell and add some shredded newspaper to absorb excess moisture and balance the bin.

8. Night time cooling

In the event of a serious heat wave (you know the ‘week of 40+ temperatures’ we often get sometime in February or March), letting the bin cool off at nighttime can be helpful.

Open the lid and cover with a wet hessian sack or old wet towel.

How do you keep your worm farm cool on hot days? Please add your comments we’d love to hear from you.

It is easier to keep your worms happy when they live in a Hungry Bin worm farm. A Hungry Bin has wheels and can moved to a cooler location. The larger mass means more depth for the worms to shelter. The larger mass takes longer to heat up. The depth creates space for large iced bottles to help create cooler zones.

Hungry Bin is now available in Perth exclusively through www.pearthworms.com.au